Vanta Nailo right after being rediscovered over 3 and a half decades later.
During the attack on the King’s Mansion during his dinner party, Vanta sacrificed himself to get everyone else out. He was sliced apart by Hulum’s shadow blades, cursed, then crushed by the falling building. With his body destroyed, his conviction to get revenge on the person who did this to him caused his soul to linger.
With Hulum’s revival as the Nightmare Czar, Vanta came back to help his former comrades as a Lingering Soul (Poltergeist) end this nightmare, allowing his soul to ascend to the next stage